The purpose of this project is to apply current methods in molecular biology to study disseminated neurofibromatosis (NF). The project involves collaboration with several NF clinical centers to insure the proper collection of tumor tissue, family pedigrees, and the preparation of EBV transformed cell lines for DNA analyses. The specific aims of the project are: (1) To select highly informative families for linkage studies in NF; (2) To test these families with specific and random DNA probes with the aim of locating a close marker to the NF gene; (3) To use possibly specific NF probes to get closer to the NF gene after a linked marker is located. Various technical possibilities are considered for speeding up the search for linked polymorphisms.